An analysis of micromovements causing a turboprop effect or a micro-Doppler was carried out, analysis of model input data for building a function bank was performed, an algorithm for reducing the effect of a turboprop effect was considered, the expediency of forming a similarity function for the subsequent reduction of the effect of micromotion on an object
Keywords: spectrum; radar; echo signal; turboprop effect; gliding component, micro-Doppler, radar
The scheme and design of the detector operating in the range of operating frequencies from at least 1 to 1250 MHz are described. An experimental study of the frequency dependence of the voltage sensitivity B_u, as well as the amplitude characteristic at four frequencies. It is shown that the detector has a high frequency response uniformity and can be used in measuring and receiving-transmitting equipment.
Keywords: the entrance detector, the voltage sensitivity, the amplitude, the unevenness of sensitivity on the voltage
This article presents the results of an experimental study of the deep cooling of natural gas combustion products in a condensation heat exchanger of a waste heat exchanger in a boiler house No. 12 at the Federal State Budgetary Educational Institution of Higher Education "National Research Ogarev Mordovia State University". The heat scheme of the boiler house with the flue gas heat exchanger provides the maximum continuous cooling mode. The study identified the factors that have the greatest impact on the efficiency of the heat exchanger-utilizer.With short-term operation of the boiler in the spring and autumn periods, the efficiency is more than 3%.
Keywords: burner, combustion mode optimization, heat utilizer, boiler room thermal circuit, boiler unit, flue gases, condensation, heat exchanger, cogeneration mode, cooled gases
Hot stamping of porous billets (GSPZ) is considered. Structural steels obtained with the use of GSPZ technology are significantly inferior in terms of machinability by cutting similar in chemical composition to cast and hot-rolled steels. Various alloying elements are considered to improve the machinability of structural powder steels by cutting and their effect on physical and mechanical properties.
Keywords: powder metallurgy hot stamping of porous billets, GSPS, machinability, alloying elements
The parameters of the porous structure and the active surface of cobalt catalysts for Fischer-Tropsch synthesis (SFT) prepared by the impregnation method have been studied. Characteristics of composition and porous structure were studied using elemental analysis and the Brunauer-Emmett-Taylor method (BET). The effect of the addition of oxide promoters on the specific surface area, pore volume and pore size of the Co / SiO2 catalyst has been studied.
Keywords: Fischer-Tropsch synthesis, heterogeneous catalyst, promoter, carrier, specific surface area, porous structure, selectivity, activity, dipping method
The parameters of the porous structure and the outer surface of cobalt catalysts for the synthesis of Fischer-Tropsch, promoted by magnesium, prepared by the impregnation method according to moisture capacity, were studied. The effect of polymorphic modification (γ, θ, α) of the carrier on the physicochemical properties of the catalyst Co-Mg / Al2O3 was studied.
Keywords: Fischer-Tropsch synthesis, polymorphic modifications of Al2O3, synthetic motor fuel, catalyst, carrier, elemental analysis, BET method, specific surface, porous structure
This paper contains an analysis of the modeling results of the electrophysical parameters of light-emitting GaInAsSb / GaSb solid solutions. The model takes into account three types of current - drift, thermionic emission and tunneling through potential barriers. In the work, graphs of radiation power versus current strength and current-voltage characteristic (IVC) of the LED device are plotted. Modeling indicators based on the features of the band structure of semiconductor systems have been built. Experimental results were discussed, which showed satisfactory agreement with the data obtained on the basis of calculations.
Keywords: solid solutions, Sim Windows 1,5, radiating structures, currents limited by space charge, electrophysical parameters
Developed approaches to measure the structural organization of systems. The concept of entropy expands and acts as an asymmetric criterion for the systems complexity. The necessity of a nonequilibrium approach to describing the interaction of physical structures and the possibility of interpreting entropy as a measure of the structural diversity of systems is shown. The validity of this approach is confirmed by a number of examples of the evolution of different systems, the structural distributions of the elements of which play an important role in modeling physical and physicochemical processes. Theoretical aspects are based on the fundamental work of D. Gibbs and L. Boltzman. The information content of the entropy concept correlates with the well-known “complementary” factor - coentropy. In this work, the evolution curves of complex systems are constructed as dependencies on statistical diversity. The symmetry of the functions of the density of entropy and coentropy with respect to the bifurcation points is discussed. It is shown that two-phase systems “liquid – vapor”, “crystal – melt” are characterized by inversion of evolutionary trajectories.
Keywords: entropy, negentropy, koentropy, orderliness measure, structural variety, normal distribution, dissipative systems, asymmetric structure, orthogonal distributions, dependence inversion
The paper presents a systematic review of recent advances in the development of polymer-matrix nanocomposites containing fibrous (sepiolite-palygorskite group) and non-swelling (kaolinite-serpentine group) clay minerals, as well as their modified forms obtained using surface reactions with organic and inorganic substances. An analysis of scientific trends and the current status of research in this area has been carried out, with particular emphasis on the influence of the types and forms of the considered mineral fillers on the properties of nanocomposites for various applications.
Keywords: polymer nanocomposites, clay minerals, kaolinite, halloysite, sepiolite, palygorskite
The article is devoted to the problem of theoretical research and development of perovskite-based solar cells to optimize their design and increase efficiency. The paper presents a numerical simulation of the transfer and accumulation of charge carriers in the planar p – i – n heterostructure of a solar cell. The simulation is based on a stationary physico-topological model based on the diffusion-drift system of semiconductor equations. The efficiency of solar cells for different perovskite film thickness was obtained. It has been established that the maximum efficiency of the optimized design of a solar cell is about 27% with a perovskite film thickness of 500-700 nm and a defect concentration in it of the order of 1012 cm-3.
Keywords: Numerical simulation, solar cell, perovskite, film thickness, defect concentration, current-voltage characteristic
It has been established that the concentration of cholesterol mesogenic esters in lubricants ambiguously affects the microrelief parameters and the tribotechnical characteristics of a steel 45 – steel 45 friction pair. %, the best indicators of friction and wear of metals, on the contrary, are realized with an increase in the concentration of cholesterol esters in lubricating compositions.
Keywords: lubricant, cholesteric liquid crystal, microrelief on friction surface, coefficient of friction
The aim of the article is to analyze the existing methods for constructing a model of random errors in micromechanical sensors. A comparison of different methods for determining the parameters of a random process model is presented: autocorrelation, power spectral density analysis, time domain analysis, and Allan variation analysis. This direction is also supplemented by considering the effect of sensor errors on the error of inertial navigation systems. In conclusion, the synthesis of forming filters for various random errors in micromechanical sensors and the results of simulation are given.
Keywords: mems gyroscope; noise analysis; stochastic drift; error modelling
When developing any technology of repair it is necessary to conduct research mikrolitrazhnyh worn parts of assemblies using metrological equipment. At the moment to improve the accuracy of research the repair company should use the latest measuring system, allowing to carry out a full complex of works on profileration surfaces of worn parts. Such devices include for example profilograph profilometer English company "Taylor Hobson", which allowed to determine the amount of allowance for machining the body of the power steering distributor. As a result, using the data obtained, the technology of repairing the power steering of KAMAZ vehicles was developed.
Keywords: metrological equipment, profilograph-profilometer, micrometer, power steering, repair technology, recovery, wear, distributor, shaft
The paper considers an adaptive on-off regulator. A block diagram of this device is given, and the sequence of operation of the blocks is also described. Simulation modeling of various types of on-off regulators was carried out in order to identify their effectiveness.
Keywords: automation, adaptive regulation, regulators, simulation
Currently, one of the main problems of our time is to improve the ecology of the regions. Green areas can contribute to this, however, the southern region of Russia is caused by a dry summer period. In this regard, there is the task of ensuring high-quality irrigation, which is often carried out by automated systems. However, without feedback, it is extremely difficult to bring the process to the proper level of quality. To do this, use humidity sensors, the price of which inevitably leads to a strong appreciation of the system. This article discusses the possibility and feasibility of developing and implementing its own moisture sensor that would meet such positive criteria as low cost, high accuracy and wide range of measurements, high corrosion resistance, versatility of application.
Keywords: soil moisture sensor, automation, irrigation, capacitive measurement method, microcontroller, Southern Federal District